Accurate dosing pump

ABSTRACT

With the subject invention, a pump is formed that generally includes a reservoir formed to accommodate at least one fluid dose, and a fluid-collecting chamber in fluid communication with the reservoir. The fluid-collecting chamber includes a dose-control portion which encompasses a volume defined by two dimensions. A first piston is disposed to urge fluid from the reservoir and at least into the dose-control portion. A second piston is disposed to reversibly slide within at least the dose-control portion of the fluid-collecting chamber. A nozzle is also provided which is located such that fluid displaced by the second piston from the dose-control portion is generally urged towards the nozzle. A check valve may be placed in the fluid path between the dose-control portion and the nozzle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This invention claims priority of U.S. Provisional Application No.60/292,949, filed May 23, 2001, U.S. Provisional Application No.60/302,847, filed Jul. 3, 2001, and U.S. Provisional Application No.60/329,963, filed Oct. 17, 2001.

BACKGROUND OF THE INVENTION

This invention relates to pumps, and, more particularly, to pumps havingaccurately-controlled dosing.

In the prior art, pumps are used for various applications ranging fromadministration of health and beauty products (e.g., hand lotion) tolubricants. With the majority of pump applications, high accuratecontrol of a dose is not critical and prior art pumps commonly have dosetolerances in the range of 3 to 5 microliters. Certain applications,however, have been developed which do require highly accurate dosecontrol. For example, pumps have been developed which deliver microdosesof ophthalmic fluid medication (5 microliters to 50 microliters), suchas those disclosed in: U.S. Pat. No. 5,152,435, issued Oct. 6, 1992;U.S. Pat. No. 5,881,956, issued Mar. 16, 1999; and, PCT Application No.PCT/US00/23206, filed Aug. 23, 2000. These references are incorporatedby reference herein in their respective entireties. As can beappreciated with all drug dispensing technology, accurately controlleddosing is absolutely necessary, particularly with small doses.

SUMMARY OF THE INVENTION

With the subject invention, various embodiments of a pump are providedhaving highly accurate control of a dose. The pump can be used invarious applications, although accurate control is particularlyadvantageous with microdosing.

With the subject invention, a pump is formed that generally includes areservoir formed to accommodate at least one fluid dose, and afluid-collecting chamber in fluid communication with the reservoir. Thefluid-collecting chamber includes a dose-control portion whichencompasses a volume defined by two dimensions. A first piston isdisposed to urge fluid from the reservoir and at least into thedose-control portion. A second piston is disposed to reversibly slidewithin at least the dose-control portion of the fluid-collectingchamber. A nozzle is also provided which is located such that fluiddisplaced by the second piston from the dose-control portion isgenerally urged towards the nozzle. A check valve may be placed in thefluid path between the dose-control portion and the nozzle.

Advantageously, with the pump of the subject invention, a simple designcan be provided which has a limited number of critical dimensionscontrolling the dose amount. Generally, the volume of the dose-controlportion of the fluid-collecting chamber controls the pump's dose. In apreferred embodiment, the dose-control portion is cylindrically shapedhaving two dimensions: a diameter and a height. As such, manufacturingvariations affecting the dose amount may be minimized with only twodimensions being implicated (and their respective tolerances) incontrolling dosing. The pumps of the subject invention can be used invarious applications, but are particularly well-suited for use withadministration of ophthalmic fluid medication.

In another aspect of the subject invention, an adapter is provided whichmay be used as an alignment aid in operating a pump.

These and other features of the invention will be better understoodthrough a study of the following detailed description and accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawing figures, which are merely illustrative, and wherein likereference numerals depict like elements throughout the several views:

FIG. 1 is a perspective view of a first embodiment of a pump formed inaccordance with the subject invention;

FIG. 2 is a schematic of the interior of the pump of the firstembodiment;

FIG. 2 a is a schematic similar to FIG. 2 but with variations of variouselements;

FIG. 3 is a schematic depicting a locking mechanism usable with thesubject invention;

FIG. 4 shows an alternatively dimensioned dose-control portion from thatof FIG. 2;

FIG. 5 is a perspective view of a second embodiment of a pump formed inaccordance with the subject invention;

FIG. 6 is a schematic of the interior of the pump of the secondembodiment;

FIGS. 7 a and 7 b are cross-sectional views of the piston of the secondembodiment;

FIG. 8 is an alternative structure of the shroud of the secondembodiment having a cut-out defined therein;

FIGS. 9 a–9 c are views showing placement of an initial prime block incausing initial prime for the first embodiment of the pump;

FIGS. 10 a–10 c are views showing placement of an initial prime block incausing initial prime for the second embodiment of the pump;

FIG. 11 shows a second version of an initial prime block usable with thesecond embodiment of the pump;

FIG. 12 is a schematic of the interior of a third embodiment of a pumpformed in accordance with the subject invention;

FIG. 13 is a schematic of the interior of a fourth embodiment of a pumpformed in accordance with the subject invention;

FIG. 13 a is a side elevational view of a pump with a set-back;

FIG. 14 is a schematic of the interior of a fifth embodiment of a pumpformed in accordance with the subject invention;

FIG. 15 is a schematic of the interior of a sixth embodiment of a pumpformed in accordance with the subject invention;

FIG. 16 is a schematic of the interior of a seventh embodiment of a pumpformed in accordance with the subject invention;

FIG. 17 is a schematic of the interior of an eighth embodiment of a pumpformed in accordance with the subject invention;

FIG. 18 is a schematic of the interior of a ninth embodiment of a pumpformed in accordance with the subject invention;

FIG. 19 is a schematic of the interior of a tenth embodiment of a pumpformed in accordance with the subject invention;

FIG. 19 a is a front elevational view of the pump of the tenthembodiment;

FIG. 20 is a perspective view of an eleventh embodiment of a pump formedin accordance with the subject invention;

FIG. 21 is a schematic of the interior of the pump of the eleventhembodiment;

FIG. 22 is a schematic of the interior of a twelfth embodiment of a pumpformed in accordance with the subject invention;

FIG. 23 is a top plan view of a spray plug; and,

FIGS. 24–27 show an adapter utilizable with the subject invention.

DETAILED DESCRIPTION OF THE INVENTION

Various embodiments of a highly-accurate dose-control pump are describedand depicted herein. As will be recognized by those skilled in the art,certain views in the drawings (e.g., FIGS. 2, 6 and 12) are combinationcross-sectional and cut-away views which illustrate the internal partsof the various embodiments. It is to be understood that aspectsdiscussed specifically with certain embodiments may be applied to otherembodiments. To simplify disclosure herein, not all descriptions arerepeated. It is also to be understood that any variation of thedisclosed elements of the several embodiments may be utilized which areconsistent with the teachings herein.

Referring to FIGS. 1–4, a first embodiment of a pump 100 is depictedformed in accordance with principles of the subject invention. The pump100 is shown to have a cylindrical body, but may be formed in othershapes. The pump 100 includes a housing 102, an end cover 104, and a cap108 which is used to actuate the pump 100. Upon actuation, a dose offluid is dispensed from the pump 100. Due to the inventive designherein, the volume of the dispensed doses can be accurately andrepeatedly controlled. The pump 100 will be primarily described withreference to FIG. 2. Some exemplary variations are shown in FIGS. 2 aand 4 and reference thereto is made appropriately.

With reference to FIG. 2, the housing 102 is mounted, for example bysnap-fit or threaded connection, to the end cover 104. A piston 106 isslidably disposed to extend through the end cover 104, and the cap 108is rigidly mounted to an end of the piston 106. The cap 108 includes atop portion 110 from which depend a side wall 112 and an interior wall114. The piston 106 is nested within, and fixed to, the interior wall114 such that a stable connection is formed between the cap 108 and thepiston 106. Ribs 116 extend inwardly from the side wall 112 which arecircumferentially spaced-apart about the side wall 112. At least one ofthe ribs 116 should be provided, although, preferably, a plurality isprovided. The ribs 116 are formed to slide within slots 118 defined inguidewall 120 of the end cover 104 in providing guidance for downwardmovement of the cap 108.

The ribs 116 may also be used as a locking mechanism for preventingactuation of the pump 100. Referring to FIG. 3, the guidewall 120 may beformed with cut-outs 121 that correspond to each of the ribs 116 thatallow rotation of the cap 108 in its rest state (as shown in FIG. 1).Stop blocks 123 are interposed between the cut-outs 121 to preventexcessive rotation of the cap 108 relative to the guidewall 120. Theribs 116 may be rotated out of registration with the slots 118, therebypreventing downward movement of the cap 108. As described more fullybelow, downward movement of the cap 108 effectuates actuation of thepump 100. To allow for actuation, the cap 108 is rotated so that theribs 116 are in registration with the slots 118. Although not shown, asan alternative, the ribs 116 may be formed on the guidewall 120 and theslots 118 on the cap 108, or a combination of ribs 116 and slots 118 maybe formed on each component.

A cap spring 122, such as a coil spring, is disposed between the endcover 104 and the cap 108 so as to urge the cap 108 upwardly and awayfrom the end cover 104 in a rest state. Preferably, the inner dimensionof the guidewall 120 is selected so as to provide columnar support forthe cap spring 122. Shoulders 124 (which may be discontinuous or acontinuous annular shoulder) are defined on the end cover 104 whichcooperate with an enlarged section 126 of the piston 106 to limit theupper extent of movement of the cap 108/piston 106 composite resultingfrom upward urging by the cap spring 122. The shoulders 124 and theenlarged section 126 also coact to define a seal with the enlargedsection 126 bearing against the shoulders 124.

A reservoir 128 is partially defined by the housing 102 to accommodatefluids, such as ophthalmic fluid medication. A pressure piston 130defines the upper extent of the reservoir 128, with the pressure piston130 being biased against any fluid within the reservoir 128 by pushspring 132. The reservoir 128 is preferably not vented to atmosphere.Accordingly, the volume of the reservoir 128 must be responsive toreductions of fluid volume located therein to prevent the formation ofvacuum and/or disruption of prime. With fluid being dispensed from thepump 100, the volume of the reservoir 128 is reduced by responsivemovement of the pressure piston 130. Preferably, the shoulders 124 aredimensioned to provide support for the push spring 132. To inhibitleakage of fluid from the reservoir 128 and about the pressure piston130, extended annular flanges 131 a, 131 b are disposed to bear againstthe housing 102 and the piston 106, respectively, so as to definetortuous leakage paths to stop fluid leakage. Other seals may beprovided, such as elastomeric rings and/or biased deflectable sealmembers 131 c (FIG. 2 a).

An end block 134 is also mounted to the housing 102 using any techniqueknown to those skilled in the art, such as a snap-fit as shown in FIG.2. Alternatively, the end block 134 may be unitarily formed with thehousing 102 as a single piece, as shown in FIG. 2 a. A bottom plug 135may also be provided to define a flat resting surface for the pump 100,as well as, to close off the interior of the end block 134. Withreference again to FIG. 2, the end block 134 defines a portion of thereservoir 128 and is formed with a fluid-collecting chamber 136 that isin open fluid communication with the reservoir 128. A dose-controlportion 138 is defined at the lowermost portion of the fluid-collectingchamber 136. With the subject invention, it is intended that fluidaccommodated in the reservoir 128 be urged into the fluid-collectingchamber 136 and, in particular, to the dose-control portion 138 by thepressure piston 130. To assist the pressure feed, the end block 134 hastapered portions 140 which converge towards the dose-control portion138. To guide sliding movement of the piston 106, as will be describedin more detail below, fins 142 may extend upwardly from the taperedportions 140 having guide edges 144 shaped and configured to limitoff-center movement of the piston 106.

In a preferred embodiment, the dose-control portion 138 encompasses acylindrical volume having a diameter Y and a height X. The piston 106 isformed with a ram portion 146 having a resilient, inwardly deflectableannular seal 148 (which may be continuous or defined by a plurality ofspaced-apart individual seal members) formed thereabout shaped to engagethe wall of the dose-control portion 138 in sealing engagement upon thepiston 106 sliding thereinto. If a plurality of spaced-apart members areused to define the annular seal 148, it is preferred that the sealmembers form a continuous annular seal upon being contracted into thedose control portion 138. Because of the dimensioning of thedose-control portion 138 and that the pumping action of the pump 100occurs only during sliding movement of the piston 106 within thedose-control portion 138, the volume of the doses administered by thepump 100 are substantially controlled by the two dimensions X, Y. Thevolume of the dose of the pump 100 is generally equal to the volume ofthe dose-control portion 138. The flexibility of the annular seal 148 ofthe piston 106 allows for responsiveness to the dimensions X, Y inurging a fluid dose towards a nozzle of the pump 100, as describedbelow.

A channel 150 extends from the dose-control portion 138 into fluidcommunication with a nozzle control chamber 152 defined within the endblock 134. A check valve is preferably disposed in the nozzle controlchamber 152 to regulate dose administration. By way of non-limitingexample, a nozzle piston 154 may be disposed within the nozzle controlchamber 152 which is urged into contact with tapered wall 156 by nozzlespring 158. As such, the nozzle 160 is sealed from the nozzle controlchamber 152 in a normal state and prevents fluid from leaking out of thepump 100 due to pressure generated by the pressure piston 130 acting onthe entrapped fluid. The nozzle piston 154 is provided with an annularnozzle seal 162 in sealing contact with a wall of the nozzle controlchamber 152. To aid in manufacturing the pump 100, the nozzle controlchamber 152 may be formed with an open end 164 through which the nozzlepiston 154 and the nozzle spring 158 may be inserted. An end plug 166may be fixed in the open end 164 using any technique known to thoseskilled in the art, including using an annular detent 168 as shown.

To limit the ingress of contaminants into the nozzle 160, a nozzle cap169 may be provided which may be removably mounted onto the end block134. In addition, or alternatively, the nozzle cap 169 may be rotatableabout the end block 134 with a cut-out or aperture 171 (shown in dashedlines in FIG. 1) being formed in the nozzle cap 169, so that the nozzle160 may be selectively exposed and covered as needed. Furthermore, anend cap 173 may be provided which is removably mountable to the housing102 to selectively cover the cap 108 (FIG. 2 a).

In use, the pump 100 is actuated by depressing the cap 108, causing thepiston 106 to translate downwardly with the annular seal 148 eventuallyentering the dose-control portion 138. Tapered portions 140 mayfacilitate contraction of the annular seal 148 upon downward descent ofthe piston 106. The annular seal 148 causes the dose-control portion 138to be sealed from the reservoir 128. Upon further downward translation,the fluid trapped within the dose-control portion 138, the channel 150,and the nozzle control chamber 152 becomes pressurized. Upon sufficientpressure build-up to overcome the spring force of the nozzle spring 158,the pressurized fluid acts against the annular nozzle seal 162 causingthe nozzle piston 154 to move away from the tapered wall 156, allowingthe nozzle 160 to communicate with the nozzle control chamber 152. As aresult, pressurized fluid rushes through the nozzle 160 and is deliveredas a dose of fluid. With discharge, pressure decays in the nozzlecontrol chamber 152, and the nozzle piston 154 is urged to its normalstate bearing against the tapered wall 156 by the nozzle spring 158.Upon releasing the cap 108, the cap spring 122 causes the cap 108 toreturn its up, rest position with the piston 106 being withdrawn fromthe dose-control portion 138. With the piston 106 being removed from thedose-control portion 138, fluid from the reservoir 128 is urged into thefluid-collecting chamber 136, and, in particular, to the dose-controlportion 138, to replace the dosed fluid under pressure from the pressurepiston 130. Any reduction of volume of fluid in the reservoir 128 isresponded to by the push spring 132 and the pressure piston 130.

The dose-control portion 138 may have various configurations dependingon the dose requirements. As discussed above, the volume of the dose isgenerally equal to the volume of the dose-control portion 138. Thus, thedimensions X and/or Y may be varied to vary the dose. In addition, thedimensions X and/or Y may be selected such that bottoming of the piston106 within the dose-control portion 138 coincides with generation ofsufficient pressure to overcome the nozzle spring 158—thus, thebottoming of the piston 106 coincides with an open state of the pump100, allowing dispensing. As shown in FIG. 4, the fluid-collectingchamber 136 and the dose-control portion 138 are dimensioned for arelatively smaller fluid dose than shown in FIG. 2.

With reference to FIGS. 5–8, a second embodiment of a pump 200 isdepicted therein formed in accordance with the principles of the subjectinvention. In contrast to the first embodiment 100, the pump 200dispenses fluid from an upper location with the pump 200 in a verticallyupright position.

Referring to FIGS. 5 and 6, the pump 200 includes a housing 202 which isfixed to an end cover 204 using any technique known to those skilled inthe art, such as a snap-fit or threaded connection. A piston 206 extendsthrough the end cover 204, and a cap 208 is mounted to an end of thepiston 206.

The end cover 204 includes a tubular shroud 210 which encircles theperiphery thereof. An interior wall 212 extends upwardly from the endcover 204, and a skirt 214 depends downwardly from the cap 208 havinginwardly protruding ribs 216 circumferentially spaced thereabout. Theribs 216 are formed to slide within slots 218 defined in the interiorwall 212. In a preferred arrangement, in a similar manner to thatdescribed above, the ribs 216 may act as a locking mechanism in beingselectively rotated in and out of registration with the slots 218.

A cap spring 220 is disposed between the end cover 204 and the cap 208to urge the cap 208 upwardly and away from the end cover 204. Shoulders222 (which may be discontinuous or continuous and annular) extenddownwardly from the end cover 204 to cooperate with an enlarged portion224 of the piston 206 in preventing upward movement of the piston 206due to the urging by the cap spring 220. Because of the rigid fixing ofthe piston 206 to the cap 208, the two components move in concert.

A webbing 226 extends inwardly of the housing 202 and is connected to acylindrical reservoir wall 228 encircling a reservoir 229 foraccommodating fluid, such as ophthalmic fluid medication. The reservoir229 may be of any diameter within the housing 202; or, alternatively,the housing 202 may define the reservoir 229 (i.e., no webbing 226 isprovided). The reservoir wall 228 terminates at one end in afluid-collecting chamber 230. The lowest portion of the fluid-collectingchamber 230 is a dose-control portion 232 which is preferablycylindrical having a diameter Y and a height X. As with the dose-controlportion 138 discussed above, the dose-control portion 232 may be ofvarying dimensions. The fluid-collecting chamber 230, and in particularthe dose-control portion 232, is in open fluid communication with thereservoir 228 to allow fluid from the reservoir 228 to be pressure fedthereinto by pressure piston 240. To facilitate the pressure feed, thefluid-collecting chamber 230 has tapered portions 234. Fins 236 mayextend from the tapered portion 234 having inner edges 238 to limitoff-center movement of the piston 206.

As with the first embodiment of the invention, the reservoir 229 is notvented but is provided with the pressure piston 240 that defines theupper extent of the reservoir 229 and is biased against fluid in thereservoir by a push spring 242. Preferably, the push spring 242 isdisposed about the shoulders 222 to be provided with additional support.Additionally, to prevent leakage about the pressure piston 240, extendedannular flanges 244 a, 244 b are disposed to bear against the reservoirwall 228 and the piston 206, respectively, and to provide tortuousleakage paths to limit fluid leakage. Other seals may be provided, suchas elastomeric o-rings, and/or biased, deflectable seal members.

The piston 206 includes a ram portion 246 having formed thereabout anannular seal 248 that is inwardly deflectable. The seal is formed todeflect and bear against the wall of the dose-control portion 238 togenerate a seal. A passageway 250 extends from the ram portion 246 andcommunicates with an inner check-valve chamber 252 defined within thepiston 206. A check-valve element 254, such as a check-valve ball asshown in FIG. 6, is disposed within the inner check-valve chamber 252.With the pump 200 in an unactuated state, the check-valve element 254seals the passageway 250 from the inner check-valve chamber 252. A bore256 extends from the inner check-valve chamber 252 to an upper end ofthe piston 206. To ease manufacturing, as shown in FIGS. 7 a and 7 b,the piston 206 may be formed with an outer sleeve 258 that extends thefull length of the piston 206, including the ram portion 246 and theannual seal 248, and a core 260 disposed rigidly therein. In preparingthe piston 206, the outer sleeve 258 is first prepared and thecheck-valve element 254 disposed therein to seat in the innercheck-valve chamber 252. Thereafter, the core 260 is inserted andaffixed to the outer sleeve using any technique known to those skilledin the art. The bore 256 may be defined by a slot defined in the core260 and/or a slot defined in the outer sleeve 258. Additionally, thecore 260 advantageously reduces the volume of the bore 256. As a result,a minimal number of strokes will be required to prime the pump 200 toallow for an initial use.

The cap 208 includes a mounting wall 262 which is secured about thepiston 206. Preferably, the mounting wall 262 is defined to providesupport for the cap spring 220. A passage 264 communicates the bore 256with a nozzle control chamber 266. A nozzle piston 268 is urged againsta tapered wall 270 by a nozzle spring 272 to seal nozzle 274. An annularnozzle seal 276 bears against the wall of the nozzle control chamber 266to form a seal therewith. As with the first embodiment, an end plug 278may be used to assemble and prepare the internal components of thenozzle control chamber 266. Preferably, a vent 279 is defined in the endplug 278 to allow the nozzle piston 268 to push against the nozzlespring 272 without compressing air located around the nozzle piston 268rearwardly of the nozzle seal 276. The vent 279 can be sized to controlthe resistance (and thus the speed) by which the nozzle piston 268 opensand closes. The vent can be utilized with the end plug of the firstembodiment, although not shown.

With reference to FIGS. 5 and 8, because of the shroud 210, a cut-out oraperture 280 must be formed therein to allow for exposure of the nozzle274 during discharge. To limit ingress of contaminants into the nozzle274, the cap 208 may be rotated so that the nozzle 274 is spaced fromthe cut-out or aperture 280 and shielded by the shroud 210.

To actuate the pump 200, the cap 208 is depressed, causing downwardtranslation of the piston 206. To make use of the pump 200 morecomfortable, a finger relief 282 may be defined in the cap 208. Uponsufficient downward translation, the annular seal 248 of the piston 206engages the dose-control portion 232 and causes the dose-control portion232 to be sealed from the reservoir 228. With further downwardtranslation, fluid trapped within the dose-control portion 232 becomespressurized, until sufficient pressure is developed to lift thecheck-valve element 254 away from the passageway 250 causing opencommunication between the dose-control portion 232 and the nozzlecontrol chamber 266 via the bore 256. As fluid is driven up the bore256, pressure within the nozzle control chamber 266 increases untilsufficient pressure acts against the annular nozzle seal 276 causing itto separate from the tapered wall 270. With such operation, a dose offluid is discharged from the nozzle 274. Pressure then decays within thenozzle control chamber 266 and the nozzle piston 268 returns to bearagainst the tapered wall 270. Also, the check-valve element 254 returnsto its rest position sealed against the passageway 250. Upon releasingthe cap 208, the cap spring 220 urges the cap 208 upwardly to its restposition along with the piston 206. With the piston 206 separated fromthe dose-control portion 232, fluid from the reservoir is urged into thedose-control portion 232 by the pressure piston 240. Any reduction influid volume within the reservoir 228 is compensated for by the pressurepiston 240.

As with all pumps, initial priming is a design consideration which mustbe taken into account. Before proper dosing of a pump, fluid must begenerally drawn through all of a working fluid passageway of a pump. Inone manner of priming, initial prime may be obtained by repetitivelyactuating the pump until several doses have been administered, to ensureproper operation. Alternatively, with reference to FIGS. 9 a–c, 10 a–c,and 11, initial prime may be obtained by causing a much larger dose tobe dispensed than the intended dose, thereby ensuring all surfaces arewetted through less strokes (ideally one stroke).

For example, with reference to FIGS. 9 a–c, the pump 100 may be modifiedto include an initial prime block 170 that is releasably mounted to thepiston 106 as shown in FIG. 9 a. The resiliency of the annular seal 148may be relied upon to hold the initial prime block 170 relative to thepiston 106. Also, an initial fluid-collecting chamber 172 is providedwith an initial dose-control portion 174 which is preferably cylindricalhaving a diameter S and a height R. The dimensions S, R are selected sothat the initial prime block 170 may be fixed therein upon being forcedby the piston 106. Also, the dimensions S, R are selected to define avolume dose sufficiently large enough to obtain initial prime with oneor more actuations of the pump 100, as needed.

The fluid-collecting chamber 136 and the dose-control portion 138 aredefined within the initial prime block 170. To achieve initial primewith minimal actuations, the volume of the initial dose-control portion174 will preferably be greater than the volume of the dose-controlportion 138. A passage 176 extends from the dose-control portion 138defined in the initial prime block 170 into communication with acheck-valve chamber 178 having a check-valve element 180 (e.g., acheck-valve ball) disposed therein.

In operation, with reference to FIG. 9 a, the initial prime block 170 ismounted onto the piston 106 and spaced from the initial fluid-collectingchamber 172. Fluid from the reservoir 128 is pressure-fed into theinitial fluid-collecting chamber 172 and, in particular, the initialdose-control portion 174. To facilitate the pressure feed, the initialfluid-collecting chamber 172 may be provided with tapered portions 173;also, fins 175 may be provided to limit off-center movement of theinitial prime block 170. Upon initial actuation of the pump 100, initialstroke of the piston 106 is caused, and the piston 106 translatesdownwardly with the initial prime block 170 being forced into theinitial fluid-collecting chamber 172, and more specifically into theinitial dose-control portion 174. During such translation, as shown inFIG. 9 b, the initial prime block 170 seals the initial dose-controlportion 174 from the reservoir 128 and causes dosing of the fluidresiding in the initial dose-control portion 174. The check-valveelement 180 prevents fluid from escaping through the passage 176 and upinto the dose-control portion 138. Due to the large volume of theinitial dose-control portion 174, excessive fluid may be urged into andthrough the nozzle control chamber 152 achieving or substantiallyachieving full priming of the pump 100. Upon release of the cap 108, thepiston 106 is urged upwardly, as described above, and out of thedose-control portion 138, as shown in FIG. 9 c. As is readily evident,the holding force generated between the initial fluid-collecting chamber172 and the initial prime block 170 must be greater than that generatedbetween the piston 106 and the initial prime block 170. The operation ofthis variation of the pump 100 is generally the same as described above,except that the check-valve element 180 throttles the fluid displacedfrom the dose-control portion 138 en route to being dispensed via thenozzle 160.

With reference to FIGS. 10 a–10 c and 11, an initial priming feature mayalso be provided for the pump 200. The initial prime block 284 ispressed into the expanded flange 244 b of the pressure piston 240 so asto be relatively fixed thereto. The fluid-collecting chamber 230 and thedose-control portion 232 are defined within the initial prime block 284.The reservoir 228 is adapted to terminate in an initial fluid-collectingchamber 286 having an initial dose-control portion 288. As with otherdesigns of dose-control portions, the initial dose-control portion 288is preferably cylindrical with a diameter S and a height R. The initialprime block 284 is dimensioned to wedge into, and be fixed relativelyto, the initial dose-control portion 288. Also, the volume encompassedby the initial dose-control portion 288 is such as to allow for fullpriming of the pump 200 upon a minimal number of actuations. Apassageway 290, which may be tapered, extends through a bottom of theinitial prime block 284 into communication with the dose-control portion232. In use, upon initial actuation and downward translation of thepiston 206, as shown in FIGS. 10 a and 10 b, the annular seal 248engages the dose-control portion 232 and causes downward movement of theinitial prime block 284. The initial prime block 284, upon entering theinitial dose-control portion 288, causes it to be sealed from thereservoir 228 and fluid trapped therein to be pressurized. Fluid isforced through the passageway 290 and up into the piston 206 in asimilar manner to that described above. The volume of the fluid definedby the initial dose-control portion 288 is greater than with a normaldose, so as to wet all surfaces and obtain proper prime with minimalactuations of the pump 200. Upon release of the cap 208, the piston 206returns upwardly and releases from the initial prime block 284. Theholding force between the initial dose-control portion 288 and theinitial prime block must be greater than the holding force between thepiston 206 and the initial prime block 284. Once primed, the pump 200operates in a similar manner to that described above, although fluidwill be trapped in the volume encompassed by the passageway 290.

As an additional variation, the initial prime block 284 may be formedwith a check valve 292 located between the passageway 290 and thedose-control portion 232. The check valve allows for flow upwardlythrough the initial prime block 284 during priming, but prevents flow offluid down into the passageway 290 during use.

With respect to FIG. 12, a third embodiment of the subject invention isdepicted and generally designated with the reference numeral 300. Unlikethe first and second embodiments of the subject invention, the pump 300may be used as a true pump mountable onto any container or reservoir.The pumps 100 and 200 require reservoirs 128 and 229 which are formed tocooperate with the pistons 106 and 206, respectively, for actuation. Thepump 300 does not need such a specially-formed reservoir.

The pump 300 includes a housing 302, a reservoir wall 304, and a cap 306which is used to actuate the pump 300. The housing 302 is mounted to thereservoir wall 304 using any technique known to those skilled in theart, such as a snap-fit or threaded connection. A piston 308 is slidablydisposed to extend through an end cover 310 which may be formedunitarily with, or separately from, the housing 302. A cap spring 312 isdisposed between the end cover 310 and the cap 306 so as to urge the cap306 upwardly and away from the end cover 310. An inner wall 314depending downwardly from the cap 306 and/or a shoulder 316 extendingfrom the end cover 310 may be provided to supply the cap spring 312 withcolumnar support. The specific structure of the cap 306 and its internalcomponents are described above with respect to the previous embodiments.In addition, the locking mechanism described above (e.g., using the ribs116; 216) may also be utilized with the subject embodiment.

The reservoir wall 304 defines a reservoir 318 which is divided into anupper reservoir chamber 318 a and a lower reservoir chamber 318 b by adivider 320. The upper and lower reservoir chambers 318 a and 318 b arein open fluid communication through holes 322. The divider 320 supportsan inner wall 324 which defines an upper fluid-collecting chamber 326.The fluid-collecting chamber 326 reduces to a dose-control portion 328defined by the dimensions X, Y. The wall 324 also terminates to hold adip tube 334 that extends from the inner wall 324 into communicationwith the lower reservoir chamber 318 b. The dip tube 334 is incommunication with the dose-control portion 328 via an inlet aperture336. A check-valve element 338 is seated in the dose-control portion 328at the inlet aperture 336 to regulate flow into the dose-control portion328. To optimally collect fluid at the bottom of the reservoir 318, abottom wall 340, partially defining the reservoir 318, may be formedtapered to converge at a well 342 into which the dip tube 334 extends.The wall 324 alternatively could reduce diameter and continue down toeliminate the dip tube 334. As with the previous embodiments, taperedportions 330 and fins 332 may be provided to facilitate filling of thedose-control portion 328 and to limit off-center movement of the piston308, respectively.

The piston 308 is formed similarly to the piston 206 described abovewith respect to the pump 200. Here, however, the piston 308 includes asecondary piston 344 defined by an end face 346 and a secondary annularseal 348. The secondary piston 344 is formed to seal thefluid-collecting chamber 326 from the upper reservoir chamber 318 a.

In operation, downward depression of the cap 306 results in an annularseal 350 of the piston 308 entering the dose-control portion 328 andcausing pressurization of fluid disposed therein. The check-valveelement 338 prevents fluid escape through the inlet aperture 336 duringsuch pressure build-up. Upon sufficient pressure build-up, fluid willcause inner check-valve element 352 to be lifted, causing opencommunication between the dose-control portion and nozzle controlchamber 354. Administration of a fluid dose is achieved in the samefashion as described above with respect to the other embodiments. Uponfluid discharge, and release of the cap 306, the cap 306 is urged to itsnatural resting position, as shown in FIG. 12, with the piston 308 beingretracted from the dose-control portion 328. Upon such retraction, thesecondary piston 344 creates a suction effect within thefluid-collecting chamber 326, causing the check-valve element 338 to belifted and fluid to be drawn into at least the dose-control portion 328.It is preferred that a volume of fluid greater than the dose-controlportion 328 be drawn into the fluid-collecting chamber 326, therebyassuring full filling of the dose control 328. Once sufficient fluid hasbeen drawn, and pressure sufficiently increases, the check-valve element338 returns to its seated position. During actuation, any excess fluidin the dose-control portion 328 will be forced about the secondaryannular seal 348 and into the upper reservoir chamber 318 a.

As will be recognized by those skilled in the art, pumps formed inaccordance with the subject invention can use different pistonconfigurations to create various pressure differentials for urging fluidfrom the reservoir, such as fluid urged from the reservoir underpressure, suction, or a combination thereof. With respect to FIG. 13, afourth embodiment of the subject invention is depicted and generallydesignated with the reference numeral 400. As with the third embodimentof the subject invention, the fourth embodiment relies on suction forurging fluid from the reservoir.

With the pump 400, a housing 402, and a cap 406 are provided formedgenerally in accordance with the same principles as described above. Apiston 408 is rigidly mounted to the cap 406 so as to move in concerttherewith. The piston 408 includes a ram portion 410 about which isdefined an annular seal 412. A reservoir wall 404 defines a reservoir414 that is separated into an upper reservoir chamber 414 a and a lowerreservoir chamber 414 b by a divider 416. The upper and lower reservoirchambers 414 a and 414 b are in fluid communication via a passageway418. The divider 416 is formed with a cup-shaped well 420 that is inopen fluid communication with the upper reservoir chamber 414 a. Thewell 420 defines a fluid-collecting chamber 422 which converges andterminates in a dose-control portion 424 that is defined by thedimensions X, Y. The annular seal 412 is formed to bear against anddefine a seal with the well 420 in the dose-control portion 424. Inaddition, the piston 408 is formed with a secondary piston 426 having aperipheral annular seal 427 that bears against and defines a seal withthe reservoir wall 404 in the upper reservoir chamber 414 a. As with thepump 300, the piston 408 preferably draws a greater volume of fluid thanthe dose-control portion 424 to assure compete filling thereof.

The piston 408 includes a passageway 430 that terminates in an innercheck-valve chamber 432 in which is seated a check-valve element 434. Abore 436 extends therefrom into communication with a nozzle controlchamber 438. The formation of the bore 436 and the elements within thecap 406 are as with the previous embodiments.

To achieve actuation, the piston 408 is forced downwardly with downwarddepression of the cap 406 resulting in eventual bottoming of the annularseal 412 against the bottom of the well 420. Tapered surface 440 may beprovided to gradually contract the annular seal 412 with downwarddescent of the piston 408. Consequently, fluid trapped within thedose-control portion 424 is pressurized and forced up through the bore436 to be dispensed from the pump 400. Upon release of the cap 406, andupward movement of the piston 408 caused by cap spring 442, thesecondary piston 426 creates a suction effect within the upper reservoirchamber 414 a which draws fluid from the lower reservoir chamber 414 binto the dose-control portion 424 via the fluid-collecting chamber 422.

It should also be noted that the housing 402 may be formed with aset-back 446 such that the cap 406 is exposed in a rest position yetfully shielded by the housing 402 in proximity to nozzle 444 (FIG. 13a).

With respect to FIG. 14, a fifth embodiment of the subject invention isdepicted and generally designated with the reference numeral 500. Here,the pump 500 is provided with a piston 502 formed in accordance with thefourth embodiment of the subject invention. In addition, a pressurepiston 504 is provided for urging fluid under pressure into adose-control portion 506 via a fluid-collecting chamber 508 fromreservoir 510 through holes 512. The dose-control portion 506 is formedwith dimensions X, Y. The pump 500 basically operates the same as thepump 400, except that the pressure piston 504 aids in urging fluid fromthe reservoir 510, in addition to suction generated by the piston 502.

In a sixth embodiment of the subject invention, as shown in FIG. 15, apump 600 is provided similar to the fifth embodiment. Here, however,piston 602 of the subject embodiment extends from cap 604 and is formedwith an annular seal 606 that is inwardly deflected upon engagingtapered surface 608. In this manner, the annular seal 606 is urged intodose-control portion 610 with the piston 602 translating downwardly tobear against wall 612 to form a seal therewith. Also, fluid is urgedfrom reservoir 614 to replenish the dose-control portion 610 only underpressure from pressure piston 616. In all other respects, the pump 600is formed and operated in accordance with the disclosures above.

As a further variation, pumps can be formed in accordance with thesubject invention where the dose-control portion and thefluid-collecting chamber are formed with generally the same width, thusavoiding a reduction in diameter of the piston upon entry into thedose-control portion. For example, with reference to FIG. 16, a seventhembodiment of the subject invention is depicted and generally designatedwith the reference numeral 700. With the present embodiment, end cover702 is provided with an upstanding inner wall 704 which encircles, andpartially defines, a fluid-collecting chamber 706. An inlet aperture 708is defined which communicates with the fluid-collecting chamber 706 anda reservoir 710.

A piston 712 is slidably disposed within the fluid-collecting chamber706 which has an annular seal 714 in bearing engagement against theinner wall 704 to form a seal therewith. The piston 712 also includes aram portion 716 that encircles a passageway 718. The passageway 718 isin fluid communication with an inner check-valve chamber 720, and theram portion 716 is preferably formed with a generally flat face 722. Ashoulder 724 protrudes from the end wall 702 so as to at least partiallybound the inlet aperture 708. A check-valve element 726 is disposedwithin the shoulder 724 to be seated at the inlet aperture 708 toregulate flow therethrough. Likewise, an inner check-valve element 728is disposed within the inner check-valve chamber 720 to regulate flowthereinto.

With the subject invention, a dose-control portion 730 of thefluid-collecting chamber 706 is defined between the shoulder 724 and thepiston 712. Particularly, the dose-control portion 730 has a height Xbetween the shoulder 724 and the piston 712, and a diameter Y equal tothe inner diameter of the inner wall 704. In contrast to the majority ofthe other embodiments, dosing of the pump 700 is a function of threedimensions, not two. With reference to FIG. 16, the dimension Z definesthe upper end of the stroke of the piston 712, and, thus, is implicatedin defining the dimension X. As such, dosage volume is a function of thedimensions X, Y and Z. With the majority of the other embodiments,dosage is a function of two dimensions X and Y.

In operation, the piston 712 is downwardly driven in concert with cap732. Upon such downward translation, fluid entrapped between the piston712 and the shoulder 724 is pressurized, eventually resulting in theinner check-valve element 728 being lifted to allow for doseadministration as described above. The stroke of the piston 712 islimited by interengagement of the face 722 against the shoulder 724.Upon upward movement of the piston 712 to return to its rest positionunder force of cap spring 734, the piston 712, due to the annular seal714 forming a seal with the inner wall 704, creates suction to lift thecheck-valve element 726 from the inlet aperture 708 to draw fluid fromthe reservoir 710 into the fluid-collecting chamber 706. With sufficientfluid having been urged into the fluid-collecting chamber 706, thecheck-valve element 726 returns to its seated position to seal thedose-control portion 730 from the reservoir 710. Pressure piston 736also bears against fluid in the reservoir 710 to pressurize it in urgingfluid from the reservoir 710 as needed.

FIG. 17 depicts an eighth embodiment of the subject invention which isgenerally designated with the reference numeral 800. The pump 800 isvery similar to the pump 700, except that piston 802 is formed to bottomout at end wall 804 instead of on a shoulder as with the seventhembodiment. Accordingly, a dose-control portion 806 is defined withdimensions X, Y as shown in FIG. 17. As with the pump 700, the dimensionZ defines stroke length and has an effect on dosage volume.

As also will be appreciated by those skilled in the art, a pump can beformed in accordance with the subject invention having the dose-controlportion defined within the cap. For example, with reference to FIG. 18,a ninth embodiment of the subject invention is depicted and generallydesignated with the reference number 900. The pump 900 includes ahousing 902 and a cap 904 for actuating the pump 900. The cap 904includes internal components as described above. An end cover 906extends across the housing 902 from which protrude upwardly anupstanding wall 908 and a piston 910. In contrast to previousembodiments, the piston 910 is stationary.

The cap 904 is formed with a downward depending inner wall 912 thatterminates in an annular seal 914 which bears against the wall 908 toform a seal therewith. A fluid-collecting chamber 916 is defined betweenthe wall 908, the piston 910, and the inner wall 912 which terminates ina dose-control portion 918 defined in the cap 904. The dose-controlportion 918 is formed with the dimensions X, Y. The piston 910 includesan annular seal 920 which is defined to be received within thedose-control portion 918 and to form a seal against the surroundingportions of the cap 904. Preferably, a tapered surface 921 is definedabout the dose-control portion 918 in registration with the annular seal920 such that the tapered surface 921 urges the annular seal 920inwardly into the dose-control portion 918 during actuation as describedbelow.

In use, the cap 904 is caused to be downwardly translated, with thepiston 910 eventually entering the dose-control portion 918 topressurize fluid therein. Pressurized fluid is dispensed from the cap904 in the same manner as described with previous embodiments. Uponrelease of the cap 904, cap spring 922 causes the cap 904 to return toits rest position, as shown in FIG. 18. Fluid is urged from reservoir924 via holes 926 under suction resulting from retraction of the innerwall 912 in the fluid-collecting chamber 916, as well as, pressuregenerated by pressure piston 928 acting against fluid within thereservoir 924.

With reference to FIGS. 19 and 19 a, a tenth embodiment of the subjectinvention is depicted and generally designated with the referencenumeral 1000. The tenth embodiment shows a pump formed in accordancewith the subject invention that is sealed to limit ingress ofcontaminants thereinto. In particular, the pump 1000 includes adeflectable member 1002 which is attached to housing 1004 so as todefine a tight seal therewith. Any technique known to those skilled inthe art may be used to attach deflectable member 1002, such asultrasonic welding. The deflectable member 1002 is preferably formed ofresilient material. A cap spring 1006 applies a biasing force againstthe deflectable member 1002 to urge it into an upward position. With thedeflectable member 1002, the pump 1000 may be hermetically sealed withonly one opening to atmosphere, that being through nozzle 1008. Anovercap 1010 may be removably mounted to cap 1012 to limit the ingressof contaminants through the nozzle 1008.

In basic respects, the pump 1000 operates in the same manner as the pump900. Upon actuation, the deflectable member 1002 deflects downwardlywith the cap 1012 to allow for administration of fluid by piston 1014.Upon returning to its rest position, suction is generated by thedeflectable member 1002. Fluid is urged from reservoir 1015 intofluid-collecting chamber 1016 and dose-control portion 1018 by bothsuction generated by the deflectable member 1002 and pressure generatedby pressure piston 1020.

As also will be appreciated by those skilled in the art, various pumpconfigurations may be utilized in accordance with the principles of thesubject invention. The previous embodiments were generally described inrelation to a pump which dispenses in a direction transverse to thedirection of pump actuation (in other words, fluid is dispensed in adirection transverse to the direction in which the cap is depressed tocause actuation). In addition, a pump can be formed in accordance withthe subject invention in which fluid is dispensed “in-line” with theactuation direction. With reference to FIG. 20, an eleventh embodimentof the subject invention is depicted and generally designated with thereference numeral 1100. The pump 1100 generally includes a housing 1102having at one end cap 1104, for actuating the pump 1100, and at anotherend nozzle 1106 for dispensing fluid.

With reference to FIG. 21, a piston 1108 is rigidly mounted to the cap1104 which is slidably disposed through an end cover 1110. The end cover1110 is preferably formed separately from the housing 1102 and ismounted thereto using any technique known to those skilled in the art,such as a snap-fit or a threaded connection. A shoulder 1112 dependsdownwardly from the end cover 1110 to engage an enlarged portion 1114 ofthe piston 1108 to limit upward movement thereof. Tapered section 1115acts as a seal against the shoulder 1112 in a rest position.

A reservoir 1116 is defined about the piston 1108 and within the housing1102. The housing 1102 includes a tapered section 1118 that converges toa well 1120 that defines a fluid-collecting chamber 1122. The well 1120also defines a dose-control portion 1124 having dimensions X, Y.Preferably, fins 1126 are defined within the well 1120 to limitoff-center movement of the piston 1108, yet allow fluid to be urged fromthe reservoir 1116 into the fluid-collecting chamber 1122 about thepiston 1108.

The piston 1108 includes a recessed section 1128 which is bound by anannular seal 1130. The annular seal 1130 is formed to slide within thedose-control portion 1124 and form a seal with the surrounding portionsof the well 1120. A nozzle piston 1132 is partially disposed within therecessed section 1128 which is urged away from the piston 1108 intobearing engagement with tapered surface 1134 by nozzle piston spring1136. In a normal rest position, as shown in FIG. 21, the nozzle piston1132 closes off the nozzle 1106.

A pressure piston 1138 is also provided which is urged into engagementwith any fluid residing in the reservoir 1116 by push spring 1140 whichbears against a collar 1142 formed on the piston 1108.

To facilitate actuation of the pump 1100, flanges 1144 may be formed onthe housing 1102 adapted to be engaged by the pointer and middle fingersof an operator, allowing for thumb actuation of the cap 1104. As such,the pump 1100 may have a syringe-like action such as with known nasalsprayers.

In operation, the cap 1104 is depressed, resulting in downwardtranslation of the piston 1108. The nozzle piston spring 1136 and thepush spring 1140 will resist such downward translation, but will notprevent such. Upon sufficient downward translation, the annular seal1130 enters the dose-control portion 1124 to pressurize fluid entrappedtherein. Upon sufficient fluid build-up, the fluid will act againstnozzle flange 1146 (which forms a seal with the annular seal 1130) tocause compression of the nozzle piston spring 1136 and, thus, separationof the nozzle piston 1132 from the tapered surface 1134. Pressurizedfluid is then dispensed from the nozzle 1106. Upon sufficient pressuredecay, the nozzle piston 1132 is returned to its rest position. Withrelease of the cap 1104, the nozzle piston spring 1136 (with the nozzlepiston 1132 bearing against the tapered surface 1134) acts against thepiston 1108 to push it upwardly to its rest position. As the piston 1108is withdrawn from the dose-control portion 1124, suction is generatedwhich urges fluid from the reservoir 1116 thereinto. In addition, withthe piston 1108 being in its rest position, the push spring 1140 urgesthe pressure piston 1138 to bear against fluid within the reservoir 1116so as to pressurize the fluid therein.

Other embodiments of the “in-line” pump are possible in accordance withthe subject invention. For example, with reference to FIG. 22, a twelfthembodiment of the subject invention is depicted and generally designatedwith the reference numeral 1200. The pump 1200 includes many of the sameelements of the pump of the eleventh embodiment. Here, in contrast tothe eleventh embodiment, an additional return spring 1202 is providedwhich acts against a collar 1204 to urge piston 1206 to a rest position.In addition, push spring 1208, which acts on pressure piston 1210, bearsagainst end cover 1212, rather than the piston 1206. Slots 1207 may beprovided which allow fluid to collect between the piston 1206 and nozzlepiston 1209 so as to generate low fluid pressure acting against thenozzle piston 1209. In all other respects, the pump 1200 is generallythe same as the pump 1100 of the eleventh embodiment and operates in thesame manner.

As an additional feature, a conventional spray plug 1300 may be usedwith either of the embodiments to provide for spray discharge of a dose.Various spray plug configurations are known in the prior art. As anexemplary embodiment, as shown in FIG. 23, the spray plug 1300 mayinclude radiating channels 1302. When fluid goes through the channels1302 and into the center of the plug 1300 where a swirling motion isimparted to the discharging fluid, causing the fluid to break up into aspray pattern. As shown in FIG. 22, the spray plug 1300 is locatedadjacent to nozzle 1214. To allow for diffuse administration, the nozzle1214 may be formed to diverge.

As can be seen from the various embodiments of the subject invention,only two dimensions are used to define the dose-control portion and,thus, a minimal number of tolerances are implicated in controlling thedosing of the pump, providing for highly accurate control of dosing.With typical prior art pumps, five to twelve dimensions are implicatedin controlling dosing amount, with each dimension having its own set ofmanufacturing tolerances. Having the dose-control portion of the variousembodiments described above being cylindrical (X-height; Y-diameter),the volume of the dose-control portion can be accurately controlled. Toillustrate the minimal tolerance effect of the formation of thedose-control portion in relation to dosing with the subject invention,exemplary tolerance ranges are provided. The following calculations arebased on a cylindrical dose-control portion having a diameter Y, aheight X, and a dose volume of 10 microliters. Since the volume of thedose of the pump is generally equal to the volume of the dose-controlportion, to provide for dosing of 10 microliters, the encompassed volumeof the dose-control portion is 10 microliters.

The following formula converts a volume measured in cubic inches toliters (where the dimensions X and Y are taken in inches):π(Y/2)² X(0.01639)=volume in microliterswhere 0.01639 is a unit conversion factor.

With the dimensions X and Y having dimensional tolerances of +/−0.001inches, Table 1 sets forth possible dose tolerances for a 10 microliterdose associated with different combinations of X and Y dimensions.

TABLE 1 Max./Min. Max. Min. Dose Dose Y Y/2 X Dose Dose VariationTolerance (in) (in) (in) Vol. (μl) Vol. (μl) Range (μl) (±μl) .060 .030.21579 10.384 9.625 .76 ±.38 .080 .040 .12138 10.334 9.670 .66 ±.33 .100.050 .07768 10.332 9.674 .66 ±.33 .120 .060 .05394 10.347 9.649 .70 ±.35.130 .065 .04597 10.376 9.633 .74 ±.37 .140 .070 .03963 10.398 9.608 .79±.4  .160 .080 .03035 10.460 9.562 .90 ±.45

As can be seen, tolerances as low as +/−0.33 microliters can beobtained. In contrast, prior art pumps have dose tolerances in the rangeof 3 to 5 microliters. As is readily apparent, the subject invention canprovide for much more accurate dose control than with prior art devices.

Pumps of the subject invention can also be manufactured economicallyusing multi-cavity molding. It is envisioned that 32 to 64 cavity moldswill be particularly useful. Due to the two dimensions of thedose-control portion, a single core pin can be used to define thedose-control portion. Core pin tolerances can be held tightly duringmanufacture and as such do not greatly cause variations in the X and Ydimensions. Shrinkage of the constituent material will also causevariations in the X and Y dimensions. However, with small dimensions,less shrinkage effect is present.

Additionally, the subject invention avoids the phenomenon of “suck back”found in prior art pumps. With prior art pumps, upon discharge, a slightvacuum is typically formed within the nozzle which causes undispensedfluid to be drawn back therein, along with contaminants from thesurrounding environment. The subject invention avoids this phenomenon byhaving fluid administered under positive pressure (i.e., fluid ispressurized upon release) and the nozzle piston returning to its closed,sealed position prior to further fluid being drawn into the nozzlecontrol chamber. Accordingly, no vacuum is formed in the nozzle controlchamber that directly communicates with the outside atmosphere. Withavoidance of the introduction of contaminants, fluids contained within apump formed in accordance with the principles of the subject inventionneed not be resistant to contaminants. For example, ophthalmic fluidmedications can be stored by and dispensed with the subject pumpswithout preservatives.

In another aspect of the subject invention, an adapter 1400 may beprovided for mounting onto any pump which dispenses in a directiontransverse to the direction of pump actuation (in other words, theadaptor 1400 is for use with embodiments other than “in-line” pumps).With reference to FIGS. 24–27, the adapter 1400 is shown in conjunctionwith the pump 100 for illustrative purposes. The adapter 1400 can beused with other embodiments of the subject invention and other pumps.

The adapter 1400 includes a generally cylindrical body 1402 from whichextends spaced-apart arms 1404. Elongated slots 1406 are defined throughportions of the body 1402 and the arms 1404. Additionally, pins 1408protrude from the pump 100 and register with the slots 1406. The pins1408 must sufficiently protrude into, and optionally through, the slots1406 to ensure sufficient interengagement between the adapter 1400 andthe pump 100 to prevent dislodgement of the adapter 1400.

The interior of the body 1402 is dimensioned to allow for telescopingover the pump 100 with minimal clearance therebetween. In addition, alip 1410 is preferably formed at the end of the body 1402 to act as astable support for the pump 100, with the adapter 1400 being in anon-use position, as shown in FIG. 27.

With the structural arrangement described above, the adapter 1400 may beslid into an upward, non-use position, thereby advantageously coveringthe nozzle 160 and preventing contamination thereof. In addition, thelip 1410 provides a resting surface for the pump 100. The pins 1408 actas a stop against the slots 1406 and prevent excessive telescoping andthus allow for proper positioning of the adapter 1400 in the non-useposition.

To use the pump 100, the adapter 1400 is slid downwardly, until the endsof the slots 1406 engage the pins 1408, and then pivoted about the pins1408 into a use position, as shown in FIGS. 24–26. In the use position,the body 1412 is preferably formed to be generally concentric with thenozzle 106 to act as an alignment aid in dispensing fluid. As shown inFIG. 24, the adapter 1400 is particularly well-suited to act as analignment aid in aligning a user's eye with the nozzle 106 is dispensingophthalmic fluid. To provide further comfort to the user of the pump100, a thumb depression 1414 may be formed in the base of the pump 100.

It is also preferred that curved surfaces 1416 be defined between thearms 1404, which match the contour of the pump 100, as shown in FIGS.24–26. With matching surfaces, the adapter 1400 may be placed into a useposition with stability relative to the pump 100 during doseadministration.

As further variations of the adapter 1400, locking detents (such asdetent 1407 shown in FIG. 24) may be provided to supply holding forcefor the adapter 1400 in the non-use and/or use positions. Furthermore,the slots 1406 need not be formed to extend completely through theadapter 1400, but rather may be formed “blind” with limited depth. Also,the adapter 1400 can be formed to telescope over the upper end of thepump if the nozzle is located there, such as with the pump 200 of thesecond embodiment of the subject invention.

As is readily apparent, numerous modifications and changes may readilyoccur to those skilled in the art, and hence it is not desired to limitthe invention to the exact construction operation as shown anddescribed, and accordingly, all suitable modification equivalents may beresorted to falling within the scope of the invention as claimed.

1. A pump for administering doses of fluid, said pump comprising: areservoir formed to accommodate at least one of the doses of fluid; afluid-collecting chamber in fluid communication with said reservoir,said fluid-collecting chamber including a dose-control portion whichencompasses a volume defined by two dimensions; a first piston disposedto urge fluid from said reservoir and at least into said dose-controlportion so that fluid may collect in said dose-control portion, saidfirst piston being continuously spaced from said entire dose-controlportion; a second piston disposed to reversibly slide within at leastsaid dose-control portion so as to selectively displace at least aportion of the fluid collected in said dose-control portion wherein,with the pump being in a quiescent state, said second piston is spacedfrom said dose-control portion; and, a nozzle, wherein said nozzle islocated such that fluid displaced by said second piston from saiddose-control portion is generally urged towards said nozzle.
 2. A pumpas in claim 1, wherein said first piston pushes fluid into at least saiddose-control portion from said reservoir.
 3. A pump as in claim 2,wherein said first piston is spring-biased.
 4. A pump as in claim 2,further comprising a third piston disposed to draw fluid into at leastsaid dose-control portion from said reservoir.
 5. A pump as in claim 4,wherein said third piston moves unitarily with said second piston.
 6. Apump as in claim 1, wherein said first piston draws fluid into at leastsaid dose-control portion from said reservoir.
 7. A pump as in claim 6,wherein said first piston moves unitarily with said second piston.
 8. Apump as in claim 1, wherein a first of said dimensions is an axiallength of said dose-control portion.
 9. A pump as in claim 8, wherein asecond of said dimensions is a diameter of said dose-control portion.10. A pump as in claim 1, wherein said dose-control portion has acylindrical shape.
 11. A pump as in claim 1, further comprising at leastone check valve disposed between said dose-control portion and saidnozzle to selectively control flow.
 12. A pump as in claim 11, whereinsaid check valve is spring-biased to close communication.
 13. A pump asin claim 11, wherein said check valve is a spring-biased piston.
 14. Apump as in claim 1, wherein said reservoir is not vented ambiently. 15.A pump as in claim 1, wherein a bore extends through said first piston,fluid displaced by said second piston being urged into said bore.
 16. Apump as in claim 1, wherein a dose of fluid is approximately equal to orequal to said volume of said dose-control portion.
 17. A pump as inclaim 1, wherein an initial prime block is initially removably mountedonto said second piston.